Handheld color measurement instrument

ABSTRACT

The specification discloses a handheld color measurement instrument capable of reading both barcodes and sample colors. The instrument includes a single color measurement engine connected to a control capable of detecting and reading barcodes. When a barcode is detected, the control updates program and/or configuration information in accordance with information contained in the barcode. When a barcode is not detected, the control operates to read sample colors.

PRIORITY CLAIM

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/180,242 filed Feb. 4, 2000 entitled “Handheld ColorMeasurement Instrument” and U.S. Provisional Application No. 60/204,090filed May 15, 2000 entitled “Programmable Handheld Color MeasurementInstrument”.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to color measurement instruments,and more particularly to handheld color measurement instruments.

[0004] 2. Description of the Art

[0005] Color measurement instruments are capable of reading colors forthe subsequent conversion of the colors to a mathematicalrepresentation. That representation can be processed using techniquesknown to those skilled in the art to perform color functions. Colormeasurement instruments include, by way of illustration and notlimitation, spectrophotometers, calorimeters, densitometers, andspectroradiometers.

[0006] A handheld color measurement instrument is disclosed in U.S. Pat.No. 5,986,769 issued Nov. 16, 1999 to Krzyminski and entitled “Hand-HeldInstrument for Reflection Measuring on Printed Sheets and Test Charts.”This instrument is used in reading “color bars” on printed sheets. Whileproviding a certain level of convenience and accuracy, this scanner isnot without its drawbacks. First, the instrument requires a handheldrule to guide the instrument along a linear path. Second, the instrumentappears to include a single photodetector. Third, the space required bythe encoder wheel limits the positioning of the support wheels.

[0007] Color measurement instruments, especially the handheld type, havelimited input devices. Typically, input is limited to a few keys, oreven a single key. Consequently, such instruments are programmed andconfigured by (a) connecting the instrument to a personal computer (PC),for example, through a serial or USB connection, (b) inputtingprogramming and configuring commands into the PC, and (3) communicatingthe commands from the PC to the instrument. Such an approach is morecumbersome and time-consuming than is desired by some operators of theinstruments.

SUMMARY OF THE INVENTION

[0008] The aforementioned problems are overcome in the present inventionwherein a handheld color measurement instrument is provided withimproved functionality and ease of use.

[0009] In a first aspect of the invention, the instrument includessupport rollers that guide movement of the instrument on a surface in alinear direction. The instrument includes a color measurement enginehaving an aperture opening through the bottom of the instrument.Consequently, the aperture scans along a line as the instrument isrolled over a surface such as a printed sheet.

[0010] In a first variation of the first aspect, the instrument housingincludes line-defining elements for defining a visual line that isparallel to the linear direction of travel and that is aligned with thescanning aperture. The elements can be one or more of wings on thehousing, notches in the housing, or lights supported by the housing. Theline-defining elements assist in aligning the instrument with a targetfor accurate scanning.

[0011] In a second variation of the first aspect, the instrument is adensitometer including a blunt nose, and the scanning aperture islocated proximate the nose. A plurality of photodetectors are arrangedin an arcuate configuration about the scanning aperture. Nophotodetector is closer to the blunt nose than the scanning aperture.Consequently, the photodetectors do not interfere with placement of theaperture closely proximate the blunt nose of the instrument.

[0012] In a third variation of the first aspect, rolling supportelements and an encoder wheel are mounted in the bottom of theinstrument. The support wheels are proximate the perimeter of the bottomof the instrument. By separating the rolling support elements from oneanother as much as possible (i.e. positioning them proximate theperimeter of the bottom), the tracking of the instrument is improved.The encoder wheel is positioned interiorly of the support elements,where room is available for the entire encoder assembly.

[0013] In a fourth variation of the first aspect, the single colormeasurement engine within the instrument is capable of reading bothbarcodes and color bars or other targets. Consequently, the instrumentcan be used to read barcode information, for example, to configure theinstrument. The instrument does not require a separate optical mechanismfor reading the barcodes.

[0014] In a second aspect of the invention, the instrument can beprogrammed and/or configured by reading barcodes using the colormeasurement engine. More specifically, the instrument includes ahousing, a color engine, and a control (e.g. a microprocessor) withinthe housing. The control is coupled to the engine and is capable ofdetecting and reading barcodes. Accordingly, programming and/orconfiguration information can be inputted into the instrument throughbarcodes. Such inputting is easy, accurate, and fast. When theinstrument does not detect barcodes, the instrument performs colormeasurement functions (e.g. as described above).

[0015] These and other objects, advantages, and features of theinvention will be more readily understood and appreciated by referenceto the detailed description of the preferred embodiment and thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a perspective view of the color measurement instrumentof the present invention scanning a color bar on a printed sheet;

[0017]FIG. 2 is a top plan view of the instrument scanning the colorbar;

[0018]FIG. 3 is a bottom plan view of the instrument;

[0019]FIG. 4 is an upper perspective exploded view of the instrumentwith the cover removed;

[0020]FIG. 5 is a bottom perspective exploded view of the instrumentwith the cover removed;

[0021]FIG. 6 is a bottom view of the optics assembly;

[0022]FIG. 7 is a side exploded view of the optics assembly;

[0023]FIG. 8 is a sectional view through the instrument taken along line8-8 in FIG. 2;

[0024] FIGS. 9-13 illustrate acceptable and unacceptable barcode for usein conjunction with the instrument;

[0025]FIG. 14 shows the barcode for the Barcodes Disabled instruction;

[0026]FIG. 15 shows the barcode for the Baud Rate 9600 instruction;

[0027] FIGS. 16-22 show the barcodes for various Configurationinstructions;

[0028]FIG. 23 is a pictorial representation of the fields within theparameter string for the Total Configuration command;

[0029]FIG. 24 shows the barcode for a Total Configuration instructionthat sets all possible switches; and

[0030]FIG. 25 is a schematic diagram of the control and communicationcomponents of the instrument.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0031] A handheld color measurement instrument constructed in accordancewith a preferred embodiment of the invention is illustrated in thedrawings and generally designated 10. The instrument includes a housing12 (FIGS. 1-3) and a color measurement engine or optics assembly 14(FIGS. 4-8). The housing includes a plurality of rollers 16 (FIGS. 3-5)to support the housing 12 for rolling movement in a linear direction D.The optics assembly 14 includes an aperture 18 opening through thebottom of the housing. When the instrument is rolled across a surfacesuch as a printed sheet, the aperture scans along a linear path such asa color bar B.

[0032] The disclosed instrument 10 is a densitometer. Alternatively, theinstrument could be any color measurement instrument such as aspectrophotometer or colorimeter.

[0033] I. Housing

[0034] The housing 12 includes a base plate 20, a heat sink 22, and acover 24.

[0035] The base plate 20 is the frame component on which the remainingelements are supported. In the preferred embodiment, the base plate 20is fabricated of plastic. Alternatively, the base plate may befabricated of any suitable material.

[0036] The base plate 20 includes an optics socket 30 for the opticsassembly, a plurality of roller sockets 32, and an encoder socket 34.The optics socket 30 is configured to receive the optic assembly 14. Theroller sockets 32 receive the support rollers 16 in a snap-fit fashion.The rollers 16 are free to rotate within the sockets 32 after beingmounted therein. Similarly, the encoder wheel socket 34 receives theencoder wheel 36 in snap-fit fashion. The encoder wheel is also free torotate after assembly.

[0037] The encoder wheel 36 is coupled in conventional fashion to anencoder (not shown) of the type generally well known to those skilled inthe art. As perhaps best illustrated in FIG. 3, the wheel 36 isproximate the front rollers 16 and the aperture 18. As used in thiscontext, proximate means that the distance between the wheel 36 andaperture 18 is no more than one-half, and preferably no more thanone-third, of the length of the instrument 10. The proximity of thewheel 36 to the aperture 18 improves the correspondence between thedistance measured by the encoder and the distance covered by theaperture.

[0038] The base plate 20 further includes front mounting bosses 40 andrear mounting bosses 42 for properly registering and securing the cover24 to the base plate 20 using fasteners (visible only in FIG. 3). Theplate 20 further defines apertures 44 for receiving fasteners (visibleonly in FIG. 3) intersecuring the heat sink 22 and the optics assembly14 to provide a thermal path between the optics assembly and the heatsink. The plate 20 further defines apertures 46 for receiving fasteners(visible only in FIG. 3) for securing the heat sink 22 to the bottom ofthe plate.

[0039] As perhaps best illustrated in FIG. 3, the support rollers 16 arelocated proximate the perimeter of the housing 12 or base 20. Thetracking of the instrument is enhanced by positioning the rollers as farapart from one another as possible. This is similar to improving thetracking of an automotive vehicle by having a wide wheel base. The axisof rotation of all of the rollers 16 are parallel to one another.Consequently, the instrument 10 tracks in a linear direction D generallyperpendicular to the axes of rotation of the rollers. In the currentlypreferred embodiment, the rollers 16 on each side of the instrument 10are substantially co-axial with one another. However, non-co-axialroller placements are also within the scope of the present invention,and may be desirable in view of instrument geometry due to functionaland/or decorative considerations.

[0040] The heat sink 22 is included to dissipate heat generated by theoptics assembly 14. As seen in FIGS. 3-5, the heat sink 22 is configuredto have a perimeter generally similar to the perimeter of the base plate20. The heat sink 22 includes support wheel cut-outs 50, an encoderwheel cut-out 52, and an optics cut-out 54. The heat sink 22 alsoincludes a recessed label area 56 within which a label (not shown) maybe mounted.

[0041] The heat sink 22 further includes front apertures 58 and rearapertures 60. The front apertures 58 are aligned with the apertures 44in the base plate 20 and the optics assembly 14, so that the heat sinkmay be secured to the optics assembly 14 to provide a thermal path. Therear apertures 60 are aligned with the apertures 46 in the base plate 20enabling the heat sink 22 to be attached to the instrument.

[0042] The cover 24 (FIGS. 1-2) is designed to be easily grasped by ahuman hand H (FIG. 1). The design of the cover 24 is symmetrical about alongitudinal line. Therefore, the instrument 10 is unhanded. The base ofthe cover 24 is generally the same shape as the base plate 20 so thatthe cover and base plate fit neatly together when intersecured. Thehousing 12, including the base plate 20 and the cover 24, include ablunt nose 62. In the preferred embodiment, the nose is generally linearand planar. However, blunt has generally understood meanings broaderthan generally linear or planar. One or more lines 61 may be provided onthe nose 62 in the form of printing, notching, or other means. Each line61 is perpendicular to the bottom of the instrument and is aligned withthe aperture 18. The lines 61 provide a visual indicator of the positionof the aperture 18 to assist in taking “spot” readings (i.e. readings ofa single spot without moving the instrument during the reading).

[0043] A button 63 (FIGS. 1 and 8) is located within a button recess 64to be easily operated by the index finger (or another finger) of theoperator. The button 63 is electrically connected to the internalcircuitry or processor 99 of the instrument 10 (see below).

[0044] The housing 12 includes several pairs of line-defining elementsor means for visually defining lines that are parallel to the lineardirection of travel and that are aligned with the aperture 18. Withparticular reference to FIGS. 1 and 2, these line-defining means includeany one of the pair of wings 70, the pair of notches 72, or the pair oflight-emitting diodes (LEDs) 74. Each of these pairs defines a line Lparallel to the direction of travel D and aligned with the aperture 18.Consequently, the pairs of line-defining elements enable the operator tovisually align the instrument 10 for linear scanning along a color bar Bor other color target.

[0045] II. Optics Assembly

[0046] The optics assembly or color measurement engine 14 includes (fromtop to bottom as illustrated in FIG. 7) a connector 80, a lamp printedcircuit board (PCB) 82, a lamp 84, a plurality of photocells orphotodetectors 86, a housing 88, an infrared filter 90, a limitingaperture 92, a lens 94, and a sizing aperture 96. The last threeelements are collectively referred to as the aperture or apertureassembly 18.

[0047] The housing 88 is D-shaped (see FIG. 6). The D shape includes aflat surface 97 which abuts the blunt nose 62 of the housing 12 withinthe assembled instrument. This enables the optics assembly 14 to bepositioned as far forward within the housing 12 as possible while stillproviding a plurality of photodetectors 86 in the assembly.

[0048] The infrared filter glass 90 is well known to those skilled inthe art and is included to block infrared (IR) radiation from reachingthe photocells 86. All of the elements within the aperture or apertureassembly 18 also are generally known to those skilled in the art.

[0049] Both the lamp 84 and the connector 80 are mounted on the PCB 82in conventional fashion. The lamp or illuminator is generally known tothose skilled in the art and in the preferred embodiment is atungsten/halogen (i.e. tungsten filament and halogen gas) lamp.

[0050] The photocells 86 are mounted in a semicircular configurationabout the aperture 18. Because the instrument is a densitometer, thephotocells are selected to be sensitive to one of the colors of cyan,magenta, and yellow to provide an ANSI/ISO Status T system response. Apair of photocells responsive to each color are arranged at 90° to oneanother. This approach enhances (over a single photocell) the accuracyand averaging of detected color by increasing the signal and by reducingorientation variation due to, for example, the grain of the media. Otherresponses and detector configurations are within the scope of theinvention.

[0051] III. Control

[0052] As illustrated in FIG. 25, the instrument 10 includes a computerprocessor, control, or other processing means 99 for controlling theoperation of the instrument and for interfacing the instrument with acomputer. The instrument also includes EEPROM memory 101 for storingmemory information such as programming information and/or configurationinformation. The processor and memory are generally known to thoseskilled in the art, and therefore need not be described in detail. Theprocessor or control 99 and the memory 101 are located in the area 100(see FIG. 8) and include appropriate communication connections with theengine 14, the input button 63, the LEDs 74, and the communicationsocket or port 98.

[0053] The instrument 10 may include both USB (Universal Serial Bus) andserial (e.g. RS232) capability, for example, as disclosed in U.S. patentapplication Ser. No. 09/411,484 filed Oct. 1, 1999 and entitled “ColorMeasurement Instrument with Multiple Protocol Interface”. Additionally,the instrument may include Internet, wireless, and/or othercommunication capabilities.

[0054] In view of the disclosure of this application, the specificprogramming of the control 99 is well within the capabilities of oneskilled in the programming art, and therefore need not be set forth indetail.

[0055] IV. Operation

[0056] The instrument 10 is easily used as a hand-held color measurementdevice. A cord (not illustrated) interconnects the instrument 10 with apersonal computer or other device (also not illustrated). Specifically,the cord is connected to the instrument 10 via the socket 98.

[0057] To scan a color bar, the instrument is grasped with the hand muchas a computer mouse would be. The instrument is positioned so as to bealigned for linear scanning across a color bar B. All of theline-defining elements facilitate the proper alignment of the instrument10 with the color bar B. As noted above, those devices include the wings70, the notches 72, and the LEDs 74. The user then depresses the button63 and rolls the instrument 10 along the color bar B. When scanning iscomplete, the user releases button 63. Because the rollers 16 guide theinstrument 10 along a linear path D, the instrument 10 tracks along thecolor bar if properly initially aligned. Only minimal, if any,corrective guidance is required by the user when scanning the color barB.

[0058] The densitometric operation of the instrument 10 is well known tothose skilled in the art. Consequently, a detailed description is notnecessary. Suffice it to say that the photocells 86 detect the lightreflected from various locations along the color bar so that theprocessor (not illustrated) can convert the photodetector outputs into amathematical representation of the scanned color.

[0059] The instrument 10 can also be configured, reconfigured, orotherwise programmed using barcode information. In doing so, a barcodeset-up sheet or sheets are provided by the manufacturer of theinstrument. The sheet or sheets include custom barcode information forconfiguring the parameters, including but not limited to the following:

[0060] Baud Rate

[0061] Separator (the character that appears between the data fields)

[0062] Delimiter (the character that indicates the end of a line)

[0063] Decimal point (can be turned on or off)

[0064] Auto Transmit (data automatically transmitted after a measurementis complete)

[0065] Data After Pass (transmits data after each pass [as opposed tocollecting all data And transmitting only when all passes have beenmeasured])

[0066] Min/Max (includes Min/Max information for selected strip data)

[0067] Times-10 (adds extra digit of precision to measured data)

[0068] Instrument Type

[0069] Turning more specifically to the configuration of the instrumentusing barcodes, the following description is provided.

[0070] The barcode system comprises a specially designed barcode formatwhich is printed on the sample to be measured by the pattern recognitionfirmware. This system uses existing densitometer optics for reading thebarcodes, eliminating the need for additional barcode reader hardware.The barcodes are imaged in the measurement path, allowing the instrument10 to measure the color patches and read the barcode with a single pass.The internal pattern recognition algorithms distinguish between thesample area and the barcode area, and handle each appropriately.

[0071] These barcodes have a number of uses, including but not limitedto the following:

[0072] 1) Instrument calibration: The calibration values may be encodedon the calibration strip along with the patches to be measured. Thisallows the user to calibrate the unit with a single pass without havingto enter calibration values manually.

[0073] 2) Strip identification: Barcodes may be imaged along with thecolor patches to be measured. This allows strips to be tagged with anidentifier code. This code can be used for lot or batch identification,verification of the correct strip, or any other use which could use asmall amount of information along with the measured color data.

[0074] 3) Unit configuration: A barcode or series of barcodes may be setup to allow the instrument to be configured without requiring the use ofexternal computers and software. The firmware in the instrument isconfigured to recognize certain sequences of barcodes. These sequencesmay then correspond to internal configuration settings. Moving the unitover the properly sequenced barcode causes it to change its internalconfiguration to match the desired settings encoded into the barcode.The set of configuration barcodes can be printed in a user manual alongwith text describing each barcode's function.

[0075] Because these barcodes are read with the same optics used tomeasure the color patches and not with a dedicated barcode reader, theirformat differs greatly from any of the established bar coding methods(such as used on UPC symbols). The method minimizes the amount of linearspace required for 8 bits of information while allowing for differingmedia contrast ratios and varying strip travel speeds. The measurementsgiven are optimized for the size of the aperture in the optics and therange of travel speeds with which the barcodes are measured. Althoughthis description specifies using black and white to encode the barcodes,and because the instrument measures the three color channelssimultaneously, the methods described herein can readily be extended touse bar codes having a plurality of portions each of a different orunique color to increase the amount of encoded information. When soconfigured, the control 99 is capable of reading the informationcontained within each of the different colored barcode portions.

[0076] The basic barcode format is as follows: 1 start bit, 8 data bitsencoded least significant bit first (nearest the start bit), and 1 stopbit. The barcode is scanned in the direction such that the start bit isthe first end to be read. Logic 1 is defined as a black area or area ofmaximum density. Logic 0 is defined as a white area or area of minimumdensity. It is important that the density of the logic 1 patches be asclose as possible to the maximum density (D-Max) found anywhere alongthe read path and that the density of logic 0 be as close as possible tothe minimum density (D-Min) found anywhere along the read path. Anythingother than D-Max or D-Min may render the barcode unrecognizable.

[0077] The start bit is 0.4 inches (10 mm) in length and is composed of0.1 inches (2.5 mm) of D-Min followed by 0.3 inches (7.5 mm) of D-Max.

[0078] Each data bit is 0.2 inches (5 mm) in length. Bits are encoded ina modified Manchester format, where each bit is composed of a D-Min areafollowed by a D-Max area. The state of an individual bit is determinedby the ratio of the length measurements of D-Min to D-Max, where a bitcomposed of mostly D-Min area is considered Logic 0 and a bit composedof mostly D-Max area is considered Logic 1. To minimize the number oflight/dark transitions and to maximize the size of each bit, theD-Min/D-Max ratio will depend on the state of the surrounding bits. Ingeneral, Logic 0 is 0.17 inches (4.3 mm) of D-Min area followed by 0.03inches (0.8 mm) of D-Max. Logic 1 is 0.03 inches (0.8 mm) of D-Minfollowed by 0.17 inches of D-Max. Exceptions to the above general ruleare as follows:

[0079] If the current bit is Logic 0 and the next bit is Logic 1, theD-Max area which would have been normally a part of the current bit isomitted and the D-Min area which would have been a part of the next bitis omitted (see FIGS. 9-10).

[0080] Stop Bit: The stop bit shall be a Logic 0 bit conforming to thegeneral specification for a data bit. The D-Max portion of this bit maybe a part of surrounding D-Max area. An example of an appropriatebarcode according to the described format is illustrated in FIG. 11.

[0081] If two or more barcodes are placed end to end, the stop bit ofthe first barcode may be partially overlaid by the start bit of thesecond barcode such that white-to-dark transition in both of these bitsare lined up. For example, FIG. 12 illustrates three barcodes placed endto end.

[0082]FIG. 13 illustrates the combining of start and stop bits of two ormore barcodes.

[0083] Measurement of the barcodes is performed using the opticsassembly 18 of the instrument 10. The proportional electrical signalfrom the photodiodes 86 is amplified and converted to binaryrepresentations by an analog to digital (A/D) converter. These binaryvalues are stored in memory for use in the pattern recognition process.As the sample is measured, the A/D values are continuously accumulatedin memory until the measurement is complete. The result is a buffer fullof binary values representative of the reflected light across thesample. A mechanical distance feedback mechanism such as the rotaryencoder enhances the recognition process for wide travel speedvariations, but is not necessary because each bit in the barcode has awell-defined transition on both sides.

[0084] After a sample set of A/D values has been accumulated in memory,the barcode recognition process begins. For black and white barcodes,only the magenta channel is used; the data from the cyan and yellowchannels are discarded. This method could however be extended to allowuse of the cyan and yellow data, along with colored barcodes, to encodethree times the amount of data in the same physical printed area. Themethod could be further extended to allow the use of combinations colorsto further increase the amount of encoded information in the samephysical printed area. The methods will be the same; therefore thisdescription will concentrate only on the use of black and whitebarcodes.

[0085] The first step of recognition is to characterize the data. Thedata is searched for the value of highest reflectance and the value oflowest reflectance. Once these limits are established, two thresholdsare computed, one at 20% of the maximum value, and one at 80% of themaximum value. These thresholds may vary and are set largely by theratio of the aperture size to the size of the transition bar between twosimilarly valued bits in the barcode. Any A/D values less than the 20%threshold are considered logic 1 (this is low reflectance, or black),and any A/D values greater than the 80% threshold are considered logic 0(this is high reflectance, or white). Anything between these twothresholds is considered transitional.

[0086] The next step is to scan through the entire sample set and searchfor the barcode patterns. This step is composed of several sub-steps.The first sub-step is to search for the start bit. This is definedsimply as a given number of contiguous A/D values all being logic 1. Iflinear distance information is available, then the start bit is definedas a linear distance of A/D values, all being logic 1.

[0087] Once a valid start bit is found, the next sub-step is to locate 8bits of data. The first data bit should appear immediately after thestart bit, with very few transitional A/D values in between. The databit is defined in the same manner as the start bit, but with fewerdefined A/D values because of the correspondingly smaller size than thestart bit. Here, logic 0 or logic 1 are allowed. Each subsequent databit should appear with very few intervening transitional A/D samplesafter the prior bit. As each bit is found, its value is recorded forlater use.

[0088] The last sub-step is to locate the stop-bit. This bit is definedas a data bit whose value is zero. The stop bit serves to frame the8-bits of data properly.

[0089] If there is a failure in any one of the above sub-steps, theentire algorithm is reset, and the search for the start bit re-commencesat the current A/D buffer position. Any recorded bit values are ignored.Once an entire byte is recognized, its value is stored, the algorithm isreset, and the search for the start bit re-commences as the current AIDbuffer position. These steps stop once the end of data is reached.

[0090] The last major step is to use the data just acquired. The datamay be used internally if it fits a defined pattern, or it may betransmitted to a host computer along with any measured strip data. Inthis case, it is up to the host computer to determine the purpose of thedata.

[0091] V. Barcoded RCI Commands

[0092] In the unit 10, barcodes conforming to special formatting rulesare recognized as RCI commands that are executed as if the commands hadbeen sent over the serial port.

[0093] A. RCI Barcode Rules

[0094] The following are the formatting rules for RCI barcodes:

[0095] 1) RCI commands may be encoded using as many barcodes asnecessary to contain the entire command.

[0096] 2) The initial barcode must be four bytes long, consisting of twobinary bytes with a bit pattern of 0×55AA, followed by two ASCII bytescontaining the two-character mnemonic of the intended RCI command.

[0097] 3) Parameters to the command must be encoded in continuationbarcodes containing the ASCII representation of the parameters.

[0098] 4) All barcodes except the very last one must be exactly fourbytes long.

[0099] 5) All barcodes (initial and continuation) except the very lastone must have the MSB (most significant bit) of the final ASCIIcharacter set to one to signal that more barcodes are necessary tocomplete the command.

[0100] B. Reading RCI Barcodes

[0101] When reading an RCI barcode, the LEDs 74 signal what is happeningin the unit 10. While scanning the initial barcode, the LEDs 74 flashslowly between off and green—the same as any normal scan. After the unit10 has recognized the initial barcode as being part of an RCI barcode,the LEDs 74 slowly flash between yellow and green. This flash patterncontinues while scanning continuation barcodes. Upon completion of theentire RCI barcode, the LEDs 74 remain steady green, indicating asuccessfully completed read.

[0102] If the unit 10 detects an error while scanning a continuationbarcode, the LEDs 74 flash quickly between yellow and green. In thiscase, the barcode scan must be started again from the beginning with theinitial barcode.

[0103] If the unit 10 properly recognizes the entire barcode, but theresulting RCI command generates an error code, the error code is notprocessed. Instead, the LEDs 74 flash quickly between yellow and greento indicate the error.

[0104] Alternatively to the LEDs 74, or in addition to the LEDs, thesignal means may include an audible, vibratory, or other human sensorysignal generator (not shown). The implementation of these additionalsignal generators is well within the capabilities of one skilled in theart.

[0105] Although any RCI command may be encoded in barcodes and executedby scanning the barcodes, this feature is intended mainly forconfiguring a unit without using the socket or port 98.

[0106] C. Specific RCI Commands

[0107] Barcode Command

[0108] Mnemonic:

[0109] BC

[0110] Usage:

[0111] bBC<cr>

[0112] Explanation:

[0113]  This command enables or disables barcode scanning. When enabled,each time a strip is read, the scanned data will be searched forbarcodes. Up to five barcodes may be placed in the read path on eachpass of a strip. When a barcode is recognized, its value is transmittedout through the port 98. When disabled, barcodes placed in the read pathare ignored. Disabling the barcodes will reduce the processing timeafter a strip is read by about one second for a 15-inch strip. Unlikeother commands which reset to a default state after the PR command (seebelow) or after the menu keys are pressed, a change to the Barcodeswitch is written into non-volatile memory and will remain in effectuntil the next change or until the entire UNIT 10 memory is reset. TheUNIT 10 is shipped from the factory with the Barcode switch enabled.

[0114] Response:

[0115] <status code>

[0116] Possible Errors:

[0117] None.

[0118] Baud Rate Command

[0119] Mnemonic:

[0120] BR

[0121] Usage:

[0122] ddBR<cr>

[0123] Explanation:

[0124]  This command causes the unit 10 to change its communication(baud) rate. The parameter dd is the two most significant digits (orthree digits in the case of 19200 baud) of the desired baud rate dividedby two (2), expressed in hexadecimal format. For example, to change thebaud rate to 9600 baud, the command 30BR<cr> would be issued. (30 hex=48decimal=96/2. The unit 10 acknowledges the command before changing itsbaud rate. If any errors are encountered while processing this command,the baud rate will remain unchanged at its previous value. Allowablebaud rates are 1200, 2400, 4800, 9600, and 19200.

[0125] Response:

[0126] <status code>

[0127] Possible Errors:

[0128]  PRM_RANGE_ERROR occurs if the desired baud rate is omitted or isnot one of the values specified above.

[0129] Configuration Command

[0130] Mnemonic:

[0131] CF

[0132] Usage:

[0133] ddaaCF<cr> (to set a switch)

[0134] aaCF<cr> (to return the current setting of a switch)

[0135] Explanation:

[0136]  This command permits reading or setting the switches containedin the unit 10. The parameter aa specifies the switch being accessed andthe optional parameter dd specifies the new setting for that switch.Omitting the data parameter causes the unit 10 to return the currentswitch setting. Switches with only two settings (off & on) are treatedthe same as switches with multiple settings, with each setting beingassigned a unique number (in this case, 0=off, and 1=on). Switch numbersand possible settings are as follows: Possible Possible Switch NumberCode Setting AXMT 05 00 off (axmt) 01 on (AXMT) DPT 06 00 off (dpt) 01on (DPT) SEP 07 00 spc (space) 01 com (comma) 02 tab 03 cr (carriagereturn) 04 crlf (carriage return & line feed) DLIM 08 00 cr (carriagereturn) 01 crlf (carriage return & line feed) X10 0A 00 off (x10) 01 on(X10) DAP 0B 00 off (dap) 01 on (DAP) M/M 0C 00 off 01 min 02 max 03 m/m(both min and max)

[0137] Each time the CF command is received by the unit 10 and a switchis modified, the modification is written into non-volatile EEPROM memory(preferably rated for a minimum of 10,000 to 100,000 writes for eachbyte. The unit 10 firmware compares the desired setting to the currentsetting and does not write an identical setting into the non-volatilememory. Therefore, it is possible to send the same settings to the UNIT10 many times without the risk of wearing out the memory device.

[0138] Response:

[0139] <status code>

[0140] Possible Errors:

[0141]  PRM_RANGE_ERROR results if a non-existent switch is selected orif the parameter (dd) is out of range.

[0142] Total Configuration Command

[0143] Command:

[0144] TC

[0145] Usage:

[0146] muccbbdsTC<cr>

[0147] Explanation:

[0148]  This command combines the BR command, the BC command, andseveral options of the CF command into one. It is intended for use withbarcodes to allow configuration of the unit without being able tocommunicate via the serial port. The eight-character parameter string isthe hex value of a packed version of the parameters for the commandsbeing combined. The entire command is aborted if any of the parametershave illegal values. The parameters of the combined commands correspondto the fields of the parameter string as follows: AXMT AutoTransmit(05CF) bit 0 (0×01) of the “cc” byte: 0 => off, 1 => on DPT DecimalPoint (06CF) bit 2 (0×04) of the “cc” byte: 0 => off, 1 => on SEPSeparator (07CF) bits 0-2 (0×7) of the “s” nybble: values as in the 07CFcommand DLIM Delimiter (08CF) bits 0-3 (0×F) of the “d” nybble: valuesas in the 08CF command X10 Times Ten (0ACF) bit 5 (0×20) of the “cc”byte: 0 => off, 1 => on DAP Data After Pass (0BCF) bit 6 (0×40) of the“cc” byte: 0 => off, 1 => on M/M Min/Max (0CCF) bits 2-3 (0×C) of the“m” nybble: values as in the 0CCF command BC Barcode (BC) bit 1 (0×02)of the “cc” byte: 0 => disabled, 1 => enabled BR Baud Rate (BR) theentire “bb” byte: values as in the BR command

[0149] Response:

[0150] <status code>

[0151] Possible Errors:

[0152]  PRM_RANGE_ERROR occurs if there are not eight hex digits asinput parameters for the command, or if any parameter value is illegal.

[0153] The above description is that of a preferred embodiment of theinvention. Various changes and alterations can be made without departingfrom the spirit and broader aspects of the invention, which are to beinterpreted in accordance with the principles of patent law, includingthe doctrine of equivalents.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A handheld colormeasurement instrument comprising: a handheld housing; a colormeasurement engine within said housing; a memory within said housing forstoring memory information related to the operation of said colormeasurement instrument; and a control within said housing and coupled tosaid color measurement engine and to said memory, said control beingcapable of determining whether said color measurement engine isreceiving barcode information or non-barcode information, said controlbeing capable of altering information within said memory in response toreceived barcode information, said control being capable of outputtingcolor data in response to received non-barcode information.
 2. A colormeasurement instrument as defined in claim 1 wherein the memoryinformation includes at least one of program information andconfiguration information.
 3. A color measurement instrument as definedin claim 1 wherein said control is further capable of distinguishingbetween barcode information of different colors.
 4. A color measurementinstrument as defined in claim 1 further comprising a signal generatorcoupled to said control, said control being capable of actuating saidsignal generator in response to the barcode information.
 5. A colormeasurement instrument as defined in claim 4 wherein said signalgenerator includes at least one of a visual signal generator and anaudible signal generator.
 6. A color measurement instrument as definedin claim 1 wherein said control means is further capable of disablingthe ability to receive barcode information after receiving non-barcodeinformation.
 7. A color measurement instrument comprising: a colormeasurement means for outputting color signals representative of colorsaligned with said engine; and a control means coupled to said engine forreceiving the color signals, for determining if the color signalscorrespond to a barcode, for outputting barcode information if the colorsignals correspond to a barcode, and for outputting color information ifthe color signals do not correspond to a barcode.
 8. A color measurementinstrument as defined in claim 7 wherein said control means further isfor determining if a barcode includes a plurality of colors and foroutputting barcode information corresponding to each of the colors.
 9. Acolor measurement instrument as defined in claim 7 further comprising asignal means coupled to said control means for providing a signal, saidcontrol means further being for actuating said signal means in responseto the received barcodes.
 10. A color measurement instrument as definedin claim 9 wherein said signal means includes at least one of a visualsignal means for providing a visual signal and an audible signal meansfor providing an audible signal.
 11. A color measurement instrument asdefined in claim 7 wherein said control means further is for disablingthe determining means after determining that the color signalscorrespond to a barcode.
 12. A digital device comprising: memory meansfor storing memory information including at least one of programinformation and configuration information; reader means for reading abarcode; and control means for altering the memory information inresponse to the read barcodes.
 13. A digital device as defined in claim12 wherein the memory information is configuration information.
 14. Adigital device as defined in claim 12 wherein: the barcode includes aplurality of portions each associated with a unique color; said readermeans further is for reading each of the portions; and said controlmeans is for altering the memory information in response to each of theread portions.
 15. A digital device as defined in claim 12: furthercomprising signal means for producing a signal; and wherein said controlmeans further is for activating said signal means in response to thebarcode.
 16. A digital device as defined in claim 15 wherein said signalmeans includes at least one of a visual signal means for producing avisual signal and an audible signal means for producing an audiblesignal.